#1

I’m seeking input on Nonenal, sometimes referred to as 2-Nonenal/6-Nonenal which is responsible for the distinct body odor that many people experience with aging. I have read online that it can occur as early as 40 years old in some people. Over the weekend I noticed it on my FIL while we were in close proximity to one another while gardening. It reminded me of how my own mother smelled shortly before she passed away. It’s not unpleasant just distinctive. My husband noticed it as well.
Since I’m aiming for longevity I hope to prevent this from developing in myself if possible. I’ve read about the persimmon based body care products that are supposed to neutralize the odor but beyond personal hygiene and the typical lifestyle advice you can find online I’m not finding much information. I was curious if anyone here has personal experience with nonenal or if any doctors or scientists here have anything to add? I have wondered if rapamycin or other longevity interventions could potentially have an impact on reducing or preventing it.

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#2

Never heard of this but I’ve probably smelled it :slight_smile:

I would think (as you do) the odour is a symptom, and eliminating the symptom with a masking agents is probably not addressing the root cause.

I do wonder what the root cause is?

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#3

I found this old (2001) article written up about very a small group of people that just attributes it normal aging. There’s nothing actionable in it unfortunately. It doesn’t seem to be a hot research topic!:blush:
“In conclusion, our results indicate that the amount of 2-nonenal in body odor, and the amount of ω7 monounsaturated fatty acids and lipid peroxides in the skin surface lipids, tend to increase with age. These findings suggest that the oxidative degradation of ω7 monounsaturated fatty acids, accelerated by lipid peroxides, may be involved in the formation of 2-nonenal, resulting in deterioration of the body odors for the middle-aged and the elderly.“

https://www.jidonline.org/article/S0022-202X(15)41198-4/fulltext

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#4

While direct evidence linking alternative splicing changes to increased 2-nonenal production is limited, several genes involved in lipid metabolism and aldehyde detoxification—processes central to 2-nonenal dynamics—are known to undergo age-related splicing alterations. These splicing changes could indirectly influence 2-nonenal levels by affecting the enzymes’ functionality.

Genes Involved in 2-Nonenal Metabolism with Age-Sensitive Splicing

  1. ALDH2 (Aldehyde Dehydrogenase 2)

ALDH2 plays a pivotal role in detoxifying aldehydes, including 2-nonenal. Age-associated splicing variations in ALDH2 may reduce its enzymatic activity, leading to decreased clearance of aldehydes and potential accumulation of 2-nonenal.

  1. SCD1 (Stearoyl-CoA Desaturase 1)

SCD1 is involved in the synthesis of monounsaturated fatty acids, which are precursors for lipid peroxidation products like 2-nonenal. Altered splicing of SCD1 with age could modify fatty acid composition, influencing the substrate availability for 2-nonenal formation.

  1. GPX4 (Glutathione Peroxidase 4)

GPX4 protects cells from oxidative damage by reducing lipid hydroperoxides. Age-related splicing changes in GPX4 may impair its function, potentially increasing lipid peroxidation and subsequent 2-nonenal production.

  1. ALOX15 (Arachidonate 15-Lipoxygenase)

ALOX15 catalyzes the peroxidation of polyunsaturated fatty acids, contributing to lipid peroxidation processes. Splicing alterations in ALOX15 during aging could enhance lipid peroxidation, thereby elevating 2-nonenal levels.

  1. FASN (Fatty Acid Synthase)

FASN is critical for de novo lipogenesis. Age-dependent splicing variants of FASN may affect fatty acid synthesis rates, altering lipid profiles and influencing the generation of lipid peroxidation products like 2-nonenal.

Conclusion

Although direct causal relationships between splicing changes and increased 2-nonenal levels remain to be fully elucidated, the age-associated splicing alterations in genes integral to lipid metabolism and aldehyde detoxification suggest a potential indirect influence. These splicing modifications could modulate enzyme activities, affecting the balance between 2-nonenal production and clearance, and thus contribute to its accumulation with age.

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#5

Discussed in the thread below.

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#6

I’ve not read much on this, so pulled together the following for people like me just learning:

A 2012 study in PLOS ONE led by Dr Susanna Mitro, then at the Monell Chemical Senses Center, found people could distinguish between the body odors of people over 75 and under 55, but not between those in their 20s and aged 45-55.

Nevertheless, Haze’s work indicates not all of us are destined to wear the scent of age. Average 2-Nonenal concentrations for those aged 40-70 was 2.6 parts per million. However, two subjects in their 60s and one over 70 produced so little 2-Nonenal that even the mass spectrometer could barely detect it – noses would have had no chance. This was half the over-60 sample in the study.

Old People Smell Different, Not Worse

If you’ve ever spent time where the elderly congregate, you may have wondered: Do old people smell different?

Well, it’s not just you. Old and young people do give off distinctive odors, according to a study just published online in the journal PLoS ONE. Researchers from the in Philadelphia and Sweden’s Karolinska Institute found that people can reliably distinguish the body odor of elderly people from a whiff of the young or middle-aged.

But contrary to the stereotype, the characteristic odor of the elderly is actually pretty neutral. And it’s a lot more pleasant than the body odor coming from younger folks — especially the guys.
Old People Smell Different, Not Worse | KUNC

Open Access PLOS paper:

The Smell of Age: Perception and Discrimination of Body Odors of Different Ages

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20–30 years old), Middle-age (45–55), and Old-age (75–95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age.

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#7

Thanks everyone for the helpful replies. I’m grateful to be part of such a kind group of people.

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#8

Query: Is there any way to lower 2-nonenal levels in aging people?

What Chat GPT says:

Yes, there are several strategies that may help reduce 2-nonenal levels in aging individuals. 2-Nonenal is a compound associated with “old person smell” and is produced when omega-7 unsaturated fatty acids (like palmitoleic acid) on the skin oxidize. Its production tends to increase with age due to hormonal changes, slower skin turnover, and reduced antioxidant defenses.

Strategies to Lower 2-Nonenal Levels

1. Proper Skin Hygiene

  • Use acidic or antibacterial body washes: These can reduce bacterial activity and oxidation on the skin.
  • Cleansers with persimmon extract (e.g., kakishibu soap in Japan): These have been shown to neutralize 2-nonenal effectively.
  • Avoid strong alkaline soaps: They can disrupt the skin’s natural pH and microbiome, potentially increasing odor.

2. Antioxidant Use

  • Topical antioxidants: Creams or lotions with vitamin C, vitamin E, or coenzyme Q10 may help reduce lipid oxidation on the skin.
  • Oral antioxidants: A diet rich in antioxidants (berries, green tea, leafy greens) or supplements (like astaxanthin, alpha-lipoic acid) may also help.

3. Diet and Lifestyle Changes

  • Reduce intake of oxidized fats: Processed foods high in oxidized oils can contribute to systemic oxidative stress.
  • Increase omega-3 fatty acids: These can balance fatty acid profiles and reduce inflammation and oxidative stress.
  • Stay hydrated: Helps with detoxification and skin health.

4. Skin Turnover and Exfoliation

  • Gentle exfoliation (e.g., with alpha hydroxy acids): Helps remove oxidized fatty acids from the skin surface.
  • Retinoids or vitamin A derivatives: Promote skin cell turnover and reduce buildup of sebum and oxidized lipids.

5. Hormonal Balance

  • 2-Nonenal production increases post-menopause and with aging-related declines in testosterone.
  • Hormone Replacement Therapy (HRT): For those who qualify and are interested, balancing estrogen/testosterone under medical supervision may reduce related skin changes. However, this is a significant intervention and must be medically justified.

Summary of Best Approaches:

Method Evidence Strength Notes
Persimmon-based soap High Widely used in Japan; effective for neutralizing odor
Topical antioxidants Moderate May help reduce oxidation on the skin
Diet high in antioxidants Moderate Supports systemic health and skin quality
Gentle exfoliation Moderate Helps remove oxidized compounds
Hormonal balance Case-dependent For some, under medical guidance

======================================================

So, these types of soaps would seem to be the best immediate option:

Screenshot 2025-05-13 at 1.22.20 PM
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#9

That’s awesome @RapAdmin! Thank you

#10

This may be related to pH.
“As a point of reference, have you ever been to a nursing home and smelled an ammonia odor? Did you think that was because the nursing home was doing a good job of house cleaning? Well that is not the case. What is happening is you are smelling the urine of very sick people in their last days. Their bodies are in a give up state, they are likely dumping any alkaline buffers they have and the body is in last ditch mode trying to maintain sufficient blood pH for life to hang on by converting the acid in their systems to ammonia. The single biggest thing those individuals need is more water for hydration and a lot of alkalizing minerals. I would venture to guess that if this were to occur in nursing homes around the country a lot of their patients would be getting better and going home.”

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#11

I disagree (with the article). When I am not drinking my urinary pH is normally around 9. I am happy with this.

#12

Below is a link to a South Korean patent application.

KR20130086395A - A composition of plants extract for removal of nonenal - Google Patents.

It provides a plant extract composition for removing nonenal, which is a causative agent of senile body odor including an active ingredient as baekbaeksu, green tea extract, witch hazel extract and tannic acid. The key to the solution is that the four extracts must be mixed together, the best of which is the highest in the content of cypress water. In addition, the plant extract composition for the removal of the elderly body odor of the present invention may be 2.5-50% by weight, green tea extract 2.0-30% by weight, witch hazel extract 1.5-30% by weight, tannic acid 1.0-25% by weight based on the total weight. . Cypress white tea, green tea extract, witch hazel extract, tannic acid are excellent in removing the senile body odor in the above weight range.

I prefer bar soap to body wash. But am thinking of experimenting with some commercial body wash with the extracts above, mixed into the body wash.

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#13

That’s a great idea. Please let us know how it goes.

My spouse is a nursing home administrator and said it can all become depressing to him if thinks about it too much. He smells it all day so I think he’d be interested in using something like that as insurance for himself. :blush:

#14

It’s purely speculation but I wonder if something like this probiotic skin spray might help?

#15

That was an interesting story you shared.
I had a similar experience with a distinct body odor this past month at the gym.

There was a woman that smelled amazing at the gym.
Like peak, most sexual smell. I think she had an orgasm either in the gym or maybe pre workout.

Went to ask the gym employee there (a female), and she agreed with me on the scent.
I think she liked the smell also, as she didn’t say anything bad about it. Guess no one else said anything to the employee about it lol
Employee did not know if the gym had a scent policy.

The woman could have been doing it as a joke, on purpose. Secretly filming reactions on video.
Or had no clue she smelled.
I searched sex scents at stores. There was nothing like that scent sold that I’ve found. It appeared to be a natural smell. Not sure if the scent is referred to as copulins. Anyone know?
Alpha female scent.

Came across this page on Pheromone’s

Not sure but this might be a bit of the old person smell, called trimethylamine.
There should not be an issue to discuss a smell with someone, good or bad. If it’s too strong, it can be distracting in some way.
Could be something going on with hormones, peptides, and perhaps other stuff for various scents.

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#16

?

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#17

That’s wild! Maybe you should have talked to her. Hahaha

I’ve had a pretty poor sense of smell for the last 35 years due to reconstructive surgery on my nose and sinuses from a car accident. A scent is usually pretty strong to others if I’m noticing it. The portable fold out lawn chair he brought with him smelled of it too. When we went out for Mother’s Day dinner the next day he didn’t smell at all. It might have been more intense because we were sweating outside while gardening.
I’ll probably not be mentioning anything to him about it but if my husband chooses to that’s fine.

Thanks for sharing your entertaining gym experience. I think scents are fascinating and under appreciated. Noticing that aroma took me back instantly to my mother’s death bed so on a certain level it was nostalgic.

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#18

Lol Yeah, I wanted to say something but it could have caused a bigger issue.
Any ideas on conversation openers in that situation?

I realized it might be advantageous for me to smell like a quality female orgasm because other females would realize I am giving one of the highest pleasures to another female.
Wanting to experience the same thing with me.
However, I cannot find the female scent in a product. If anyone knows of any products, please share.

That stinks (no pun intended) you have a poor sense of smell due to the surgery.
Your husband could look into trying various scents to use if there are no rules on scents where he works.
Perhaps adding pheromones to it also.
Maybe various products for skin use, hair use, clothing use etc. Could cause too much attraction but it would be a fun experiment. Maybe a oil diffuser in his office.
It might cause others around him to try and smell better for him. Maybe ask him what he uses and buy it.

@John_Hemming Great link!
“synthetic copulin solution was 78.38% acetic acid, 13.21% propanoic acid, 4.94% butanoic acid, 0.76% methylpropanoic acid, and 2.14% methylbutanoic acid diluted with distilled water to a concentration of 0.08 per ml. The acid percentages are from the concentrations of acids recorded during ovulation”

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#19

I’m afraid I’ve been married too long to know about conversation starters. :slight_smile:
A 20ish y/o lady at the gym told me I was beautiful tonight but I don’t think she meant anything by it. I thanked her and told her I really appreciated it because at 55 I tend to compare myself to the younger me. She said she would have guessed 30’s! Maybe you could try telling someone they are beautiful? It really made me feel good.
My husband does use a scented candle wax melter in his office and people comment that it smells good. I’m afraid if he actually smelled really good it would turn into a nightmare since most of his employees are females.
Please let us know if you make the fragrance!

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#20

I think a lot of the stuff above might be AI hallucination, to be honest. The models don’t do well when there is scant material to actually analyse.

However, it does seem that certain lipids and short chain fatty acids are important. When I think of those two things, my mind immediately goes to microbiome. Bacteria are a major source of metabolites and SCFAs. So maybe there’s something with the skin microbiome of elderly folks?

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