Skincare extends well beyond the products people put on their faces. What you eat and the supplements you take can significantly influence the condition of your skin, hair and nails, with collagen quickly becoming a go-to solution for achieving all three - particularly one supplement that's generating buzz after a 60 year old woman credited it with helping her appear 40.

The brand iHerb - a worldwide online retailer specialising in vitamins, minerals, supplements and other health and wellness products - offers a standout product in its California Gold Nutrition Collagen. Customers can secure 20% off using the code 20COLLAGENUK, priced at £27.33 for a 462g pack, which works out at 30p per day.

Collagen is a protein that occurs naturally in the human body, though its production declines with age, which is where supplements can be especially beneficial. The California Gold Nutrition Collagen arrives in powder form and comprises marine-sourced collagen peptides, hyaluronic acid and vitamin C.

Customers are advised to blend one scoop of the collagen (5g) daily into 180-240ml of room temperature water or juice before mixing thoroughly. Overall, each bag delivers roughly 93 servings.

It features unflavoured, non-bovine, hydrolysed fish collagen and is ideally suited to supporting hair, skin, nails, joints and bones. It should be taken on an empty stomach at least one hour before or two hours after eating.

Another option worth considering is the Revive Collagen Enhanced Plus Liquid Hydrolysed Marine Collagen Sachet, available at £35.99, down from £44.99, on Lookfantastic. Sold in boxes of 14 sachets, this product is described as a food supplement blend containing collagen, aloe vera and hyaluronic acid. Simply mix into a glass of water before consuming, and it is suitable for a wide range of skin types.

For those seeking a more affordable alternative, the Unfabled Collagen Gummies 60s are available for £13.99 at Boots. Described as 'delicious, orange-flavoured' daily gummies, each one provides 1000mg of hydrolysed collagen, alongside a beauty boost of biotin and selenium to help maintain glowing hair and skin, reports Wales Online.

The California Gold Nutrition Collagen has garnered an impressive rating of 4.7 out of 5 stars on the iHerb website. One reviewer wrote: "First of all, the wrinkles on my hands have become less noticeable, and my nails and thighs have become shinier. It's safe because it doesn't contain any beef-derived ingredients.

"The taste isn't too fishy, and it's easy to drink. I've switched to a subscription, and I'm looking forward to using it even more. As per the suggested use, I take one scoop (5g) per day, at least one hour before meals or two hours after meals on an empty stomach, dissolve well in room-temperature water and drink."

Another satisfied customer commented: "I have gone through some poor health and was looking very old, my skin was dry and wrinkled, having just turned 60. I have now taken this for a year and everyone comments on how good my skin looks people say I look 40 so that is great for my ego, and frankly I feel it in my bones and joints, I believe this collagen really works and works well.

"It's expensive but it is worth every cent. I keep coming back to this as I have tried many different collagen preparations and this is the best. High quality, neutral taste easy to take, great size, excellent packaging to keep fresh."

Not every reviewer was wholly won over, however, with a handful docking a star from their ratings. One shopper observed: "This is a good quality collagen drink, the ingredients are good quality and the pack size is good. The taste needs masking, because there is a fishy back taste, it also dissolves better in warm water as per instructions. I think consistent use is best for it. The packaging is ok, have to take care re-sealing."

On the whole, the vast majority of buyers expressed their delight with the product, including one reviewer whose feedback was translated from Ukrainian: "The impressions are very positive. The skin began to look better - more moisturized, tightened, small wrinkles are less noticeable.

"Hair began to fall out much less, nails became stronger and stopped peeling. Joints became less sensitive, especially after physical exertion. Collagen dissolves easily in water or a smoothie, there is a slight fishy taste. Another advantage is the large, economical packaging. Overall, I am satisfied: a high-quality product, there is a real effect. You need to take collagen peptides, not just collagen."

iHerb is presently offering California Gold Nutrition Collagen at £27.33 for individual orders when using the code 20COLLAGENUK.