NeoGenesis Eye Serum

Our skin makes fewer of them as we age. This is a big part of why older skin heals slower and looks less bouncy.

The idea behind putting them in skincare is to "top up" the supply from the outside.

"Conditioned media" sounds mysterious but it's basically just leftover broth.

They're made in a lab where scientists grow human skin cells (fibroblasts) in a nutrient liquid. These cells release a cocktail of helpful proteins into that liquid as they live and grow.

Then, these cells are filtered out and the ingredient is the "conditioned" liquid now full of secreted goodies.

So what does neonatal mean here? It just means the original cells came from newborn tissue (usually donated foreskin), which tend to be younger, more active, and better at pumping out growth factors than adult cells.

Technically, this isn't one single ingredient, it's a mix of dozens of active molecules working together, including:

Studies find growth factor conditioned media can help with:

The evidence behind this ingredient is pretty solid too (and not just marketing).

A 24 week study of a fibroblast conditinoed media serum showed measurable improvements in the look of photodamaged skin, and these results were backed by actual skin biopsies rather than just before/after photoshoots.

And a broader review that pulled together many growth factor studies came to a similar conclusion: they generally help with fine lines, texture, firmness, and are well-tolerated.

It's also worth knowing the caveat that the review pointed out most of these serums also contained peptides, antioxidants, and exosomes.

The honest answer is there isn't a tidy "use at 1-2%" number the way there is for something like niacinamide.

This is because conditioned media isn't a single molecule. Brands add it as a percentage of a finished formula so that number is all over the map.

The serums built around it usually advertise very high levels (~50%) while others just use a splash. And the individual growth factors floating inside are actually present in very tiny amounts (think nano/micrograms per gram).

Here's one regulatory anchor point: the FDA has approved a wound healing gel that uses a pure growth factor at 0.01% (100 micrograms per gram). This shows the active growth factors themselves work at very low concentrations.

So the "50%" numbers you see on labels refer to the diluted broth and not the pure proteins.

The single most important thing to understand growth factors is that they are very fragile.

Dr. Zoe Draelos wrote this about them for Dermatology Times:

Independent lab work backs up the fragility.

Many growth factors lose a big chunk of their activity within a day or two sitting in water at room temperature and this is why smart formulating matters so much. Airless pumps, water-free formulas, and cool storage all help the ingredient survive long enough to do something. It's also a green flag if a brand can show real stability testing.

None of this means growth factor serums don't work; plenty of people get lovely results. It just means the formulation and packaging are doing a lot of the heavy lifting.

You may have heard a worry that growth factors "feed" skin cancer because their whole job is to encourage cells to multiply (this is called mitogenic activity).

It's a fair question to ask so here's the actual picture.

The theoretical concern is real enough that dermatologists take it seriously. There IS a hypothetical worry that they can encourage the wrong cells to grow in skin that already has sun damage or pre-cancerous spots.

Due to this, the cautious advice is to check with your dermatologist before using growth factor products if you have psoriasis, a history of skin cancer, or a lot of pre-cancerous sun damage.

Now the reassuring side:

There has been no documented pattern of growth factor products causing skin cancers despite millions of units sold over many years.

A large safety review of pure PDGF (one of the growth factors in these blends) found it to be non-toxic, non-mutagenic, and non-carcinogenic across decades of medical use. This is including repeated daily application to open wounds.

And a dermatology review specifically looking at topical EGF found no evidence that it stimulates cancer cells to grow (partly because these proteins are large and mostly stay near the surface).

The bottom line for a healthy person with no specific risk factor:

Growth factor conditioned media has a strong track record and is generally considered safe and well tolerated.

But be sure to loop in your dermatologist first if you have psoriasis, active or past skin cancer, or heavy sun damage. This is not because it's proven dangerous but because it's a sensible precaution while the long-term research keeps building.

The US allows human-derived growth factors so Human Neonatal Fibroblast Conditioned Media appears on labels.

In the EU, human-cell-derived ingredients are banned in cosmetics. EU products use plant-derived alternatives (barley is a common one) to get a similar effect.

Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.

Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.

This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.

Just know very high concentrations (>40%) can feel tacky in low humidity.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

Overall, HMC is a gentle and supportive ingredient. Further research is needed on the claims that this ingredient can "erase dark circles".

This ingredient can also be found in pill medicines to help our bodies digest other ingredients.

This ingredient calms down a specific inflammation signal in your skin cells (called IL-6). When left unchecked, this signal triggers enzymes that break down collagen and elastin.

Clinical testing showed statistically significant improvements in:

Studies also found the more of this ingredient used, the more your skin produces Collagen I, fibronectin, and hyaluronic acid.

You'll likely see this ingredient paired with Palmitoyl Tripeptide-1 in the well-known Matrixyl 3000 complex for enhanced anti-aging effects.

A 3% concentration applied twice daily for two months showed meaningful skin rejuvenation results in clinical panels.

Fungal acne note:
Usually a palmitic acid component can feed Malassezia in unbound form, but here is is covalently bonded to the peptide. This means it is very difficult for Malassezia to access, and therefore very unlikely to cause fungal acne.

Once there, it acts as a matrikine, a signaling peptide that prompts fibroblasts to produce more collagen, fibronectin, and hyaluronic acid.

In vitro studies show it can boost collagen production in skin cells even when UV-damaged skin samples were treated with it at a tiny concentration (it almost fully restored dermal collagen at 5ppm). It achieved this at 100x lower concentration than retinoic acid, which needed 500 ppm to do the same thing.

Human clinical data is promising, but modest:

A study of 23 female volunteers found a small but statistically significant increase (~4%) in skin thickness after treatment at 4 ppm.

A separate small trial of 15 women showed statistically significant reductions in wrinkle length, depth, and skin roughness after applying it twice daily for four weeks.

You'll likely see Pal-GHK paired with Palmitoyl Tetrapeptide-7 as part of the Matrixyl 3000 complex.

Fungal acne note:
Usually a palmitic acid component can feed Malassezia in unbound form, but here is is covalently bonded to the peptide. This means it is very difficult for Malassezia to access, and therefore very unlikely to cause fungal acne.

As a preservative, it works by disrupting the membrane of microbial proteins. This helps keep bacteria and fungi from growing in your products.

The sensitization picture is actually quite assuring as well:of nearly 71,000 patients patch tested with benzyl alcohol, only 0.21% showed a positive reaction with most of them being weakly positive.

This led researchers to conclude that benzyl alcohol cannot be regarded as a significant contact allergen.

It is worth noting this ingredient is classified as one of the EU's regulated fragrance allergens and restricted to 1% in finished products.

Labels must also declare it in concentrations above 0.001% in leave-on products and 0.01% in rinse-off products.

At concentrations around 5%, localized redness and itching can appear as a direct irritant response and not as a true allergic reaction.

It is effective at low concentrations (<0.6%). Clinical studies have found it to be non-irritating, non-sensitizing, and non-photosensitizing.

Because lactic acid molecules are larger than glycolic acid, they don’t penetrate as deeply. This means they’re less likely to sting or irritate, making it a great choice for beginners or those with sensitive skin.

Like glycolic acid, it can:

Lactic acid also acts as a humectant (like hyaluronic acid). It can draw water into the skin to improve hydration and also plays a role in the skin's natural moisturizing factor (NMF) in the form of sodium lactate.

Studies show it can boost ceramide production to strengthen the skin barrier and even help balance the skin’s microbiome.

To get results, choose products with a pH between 3-4.

Lower strengths (5-12%) focus on surface exfoliation; higher strengths (12% and up) can reach deeper in the dermis (deeper, supportive layer) to improve skin texture and firmness over time.

Though it was originally derived from milk, most modern lactic acid used in skincare is vegan. It is made through non-dairy fermentation to create a bio-identical and stable form suitable for all formulations.

When lactic acid shows up near the end of an ingredient list, it usually means the brand added just a tiny amount to adjust the product’s pH.

Legend has it that Cleopatra used to bathe in sour milk to help reduce wrinkles.

Lactic acid is truly a gentle multitasker: it exfoliates, hydrates, strengthens, and brightens. It's a great ingredient for giving your skin a smooth, glowing, and healthy look without the harshness of stronger acids.

Read more about some other popular AHA's here: