Retinol (retin-A) and retinyl palmatate are vitamin A and work on wrinkles and photodamaged skin by exfoliating the cells and encouraging new ones to form. Altough they work, they can be unbearably irritating for sensitive types. Retinaldehyde (retinal) can be converted by the body to either retinoic acid or retinol (which, in turn, can be converted to retinyl palmitate). Because of this metabolization, treating the skin with retinaldehyde could be effective, while reducing the side effects associated with heavy guns. That’s the theory anyway; but does it work in practice?
It would appear so. A French study that lasted for a year tested 21 people with a 0.05% retinaldehyde formula and concluded that it had resulted in a “significant” increase in epidermal thickness and elasticity. However, this study was conducted in the last century, well 1999.
A more recent study (2008) looked at all the retinoids (3-cis-retinoic acid (isotretinoin), retinol, retinaldehyde, tazarotene, and adapalene) and concluded that they help against hyperpigmentation and said "topical retinoids stimulate the cell turn-over of epidermal keratinocytes and promote a decrease in melanosome transfer and a rapid loss of melanins via epidermopoiesis. Topical retinoids are also involved in the control of cell differentiation." However, the study didn't report on whether one form was better than another.
So is retinaldehyde a proven improvement. It might well be. A Swiss study concluded: "Retinaldehyde, which is fairly well tolerated, seems to be the most efficient cosmeceutical retinoid; it has significant efficiency toward oxidative stress, cutaneous bacterial flora, epidermis renewing, and photoaging."
Like Osmosis Replenish, Boost is a refreshingly simple, yet powerful formula. It also has niacinamide, another ingredient that prevents hyperpigmentation, in this case by suppressing melanin production on the surface of the skin. Note also that there is antioxidant beta glucan and chlorella, an extract that is loaded with amino acids such as lysine, proline, glycine, and alanine, all of which are the essential building blocks of proteins and constitute each individual collagen unit.
Ingredients in Osmosis Boost
Purified Water, Niacinamide, 1,3 Beta Glucan, Chlorella, R-Lipoic Acid, Xantham Gum, Japanese Honeysuckle, Ethyl Alcohol, Retinaldehyde (.2%)