A question from my first Twitter chum, Musicalhouses.

Dear Colin, How can we guess how much retinol there is in a skincare product? It’s quite hard to get a percentage ge since companies don’t disclose this. In particular, I’m looking at the Hada Labo Retinol Lifting and Firming Lotion (Ingredients: water, butylene glycol, glycerine, PEG-20 sorbitan isostearate, caprylic/capric triglyceride, methylparaben, PPG-10 methyl glucose, ether, sodium Hyaluronate, triethanolamine, Carbomer, hydroxyethylcellulose, tocopherol, BHT, disodium EDTA, hydrolyzed collagen, hydrolyzed soy protein, limnanthes alba (meadowfoam) seed oil, retinyl palmitate, helianthus annus (sunflower) seed oil, sodium Everglades Hyaluronate, zea mays (corn oil) thioctic acid, beta carotene), since retinol appears all the way down there in the ingredients list and it doesn’t have the characteristic smell or colour (white to off-white yellow) of most retinol-containing products I’ve used in the past. Also, I’d be interested in knowing any rules of thumb you have for guessing the % of a skincare ingredient given how far up or down the ingredients list it is. Thanks!

Retinol is one of the few so called active ingredients used in cosmetics that actually does something.  But as a savy consumer and beauty blogger (see Musicalhouses knows  you have to have enough to have an effect.  

There is a reasonable amount of scientific back up showing that retinol does indeed improve the condition of aged skin.  The strongest plank is an independent study published in 2007 that showed retinol at a concentration of 0.4% applied three times a week for six months could significantly reverse cellular damage in mature skin.  The effects were certainly real, but maybe not as spectacular as you might suppose from marketing claims made for retinol.  That is also a heck of a lot of retinol applied for a seriously long period of time.

Sadly, there is nothing that obliges companies that sell retinol products to put the content on their packs.  You can get some idea from the colour.  Retinol does have a distinct yellow colour.  Unfortunately so do other ingredients.  For instance, beta carotene.  And this is exactly what we see on the list on Musicalhouse’s pack.

To be scrupulously fair, beta carotene is a member of the vitamin A family and may have some retinol like effects itself.  But it won’t work as well as the real thing.  In fact, there isn’t any actual retinol in this formulation since it is included in the form of retinyl palmitate.  This is an ester of retinol which breaks down to release retinol on the skin.  This probably works as well as retinol if applied regularly.  But the trial was done on a high level of actual retinol, so that is the only ingredient we have proof for.  There is a certain amount of faith involved in using a substitute.

So on the whole, this ingredient list and the description don’t inspire a huge amount of confidence.  I e-mailed the company asking about their retinol content.  Sadly, they didn’t answer.

As regards rules of thumb for reading ingredient lists, there isn’t a huge amount you can tell.  There rules say that anything below 1% can appear in any order – so it isn’t always the case that ingredients are in strict quantity order.  The rules are not enforced particularly strongly in most countries and some smaller companies either ignore them or make genuine errors.  And even big companies can get things wrong from time to time.  I have seen the same ingredient appear twice on the list of a really big household name’s product to give just one example.  I am afraid that the only way to be really sure whether a product does what you want it to do is to try it and see.


Improvement of Naturally Aged Skin With Vitamin A (Retinol)  Reza Kafi, MD; Heh Shin R. Kwak, MD; Wendy E. Schumacher, BS; Soyun Cho, MD, PhD;Valerie N. Hanft, MD; Ted A. Hamilton, MS; Anya L. King, MS; Jacqueline D. Neal, BSE; James Varani, PhD; Gary J. Fisher, PhD; John J. Voorhees, MD, FRCP; Sewon Kang, MD Arch Dermatol. 2007;143:606-612


13 thoughts on “Retinol

  1. Colin Post author

    The yellow colour develops slowly on exposure to the air. If it is a pharmaceutical product you have, Retin-A or Stieva-A are good examples, they take a lot of trouble to avoid oxygen during manufacture. Even so if you keep the tube for long enough I’ll predict it will beging to go yellow. But you’ll get more benefit if you use it quickly because it isn’t very stable and will lose its potency on standing.

  2. Musicalhouses

    Great post, thank you! Yes I have noticed that my prescription retinol creams do have that yellow colour and odor over time. So sometimes I feel like product with that same colour and odor are probably more likely to have some concentration of retinol that inspires more confidence. If on the other hand, it remains nice and white for months and has no smell, it probably doesn’t have all that much retinol after all, especially if the packaging isn’t airtight.

  3. Pedro

    It’s made by Rohto, a big pharmaceutical Japanese company and the ingredients list is wrong. Here is the correct one:

    Water, Butylene Glycol, Glycerin, PEG-20 Sorbitan Isostearate, Caprylic / Capric Triglyceride, Methylparaben, PPG-10 Methyl Glucose Ether, Sodium Hyaluronate, Triethanolamine, Carbomer, Hydroxyethylcellulose, Tocopherol, BHT, Disodium EDTA, Hydrolized Collagen, Hydolyzed Soy protein, Limnanthes Alba (Meadowfoam) Seed Oil, Retinyl Palmitate, Helianthus Annuus (Sunflower) Seed Oil, Sodium Acetylated Hyaluronate, Zea Mays (Corn Oil), Thioctic Acid, Beta Carotene.

    Anyway, since it’s just a “tonner” (“lotion” is how “tonner” is called in Japan) and Hada-Labo is a brand for sensitive skin, I also believe the amount of retinoids is very low.

  4. Colin Post author

    In theory beta carotene ought to work about as well as retinol since it breaks down to release retinol and some similar molecules. I haven’t seen any serious studies of its effect on the skin though.

  5. Melanie

    Fantastic post. It really is impossible to know what percentage of an ingredient is in a product. That’s always a sticker for me, I never quite trust product claims due to this factor.

    Good info.

  6. Janelle Lee

    Thank you for posting about this. I learned a lot. Quick question: Will retinol really affect the color of the product? I mean, it will be easier to detect if that’s the case… Just a thought.

  7. Dr Tom Walker

    Beta carotene is much more stable at room temperature than tretinoin and retinol.

    If you put a spot of various different retinol containing products on a while tile and observed the colour change with time, then the one containing more retinol should change colour quicker.

  8. Colin Post author

    That is a neat idea Tom. With a spectrophotometer you could even quantify it with a bit of work.

  9. Steve

    I’ve not seen any evidence for beta carotene so stability is irrelevant if you are looking for activity. The retinol data is much stronger than most of the esters mentioned (retinal palmitate, acetate). All the “active” retinoids have another potential downside other than the oxidation & discolouration; irritation. It is known that an initial temporary scaling and or reddening can occur in the first few uses of active product. For some this is tolerable and eventually gives way to better quality skin. This can be managed in several ways including gradual introduction (every other day – but I always advise using these product at night since they will break down in sunlight).
    However retinyl propionate may be worth looking for – it has a higher efficacy/irritation profile than others. It has been incorporated into a product with other anti-ageing ingredients.

  10. Livvi

    Retinol really is everywhere these days! I keep meaning to have a good read of the literature, I was on Roaccutane maybe more than 7 years ago and couldnt really find much out about it. But since starting my PhD (in stem cells) there is always emphasis on cultures with / without RA in. Therefore I assume it somehow has an effect on differentiation of skin etc? I wonder what the different effects are with topical versus ingested. any thoughts?

  11. Colin Post author

    Roaccutane is isotretinoin which is a more potent retinoid than retinol which is used to treat acne – I am sure Livvi knows this but some readers may not. It’s not permitted in cosmetics. I don’t think that retinol behaves on the skin at all the same way as it does in most cell culture work. There is a lot of P450 like activity going on in the skin so the retinol doesn’t really remain in its original form for very long. I don’t have time to keep up on it, but last time I looked nobody knew what its mode of action was in the skin but the end result is stimulation of collagen production. I haven’t heard of it affecting differentiation in the skin, nor of isotretinoin doing so. Both are used topically and orally, and both are widely prescribed so you’d think if they did it would have been noticed by now. It’s an interesting point though.

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