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科普一下AHAs and vitamin C products

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04-04-08 14:57操作
只看楼主AA分享不感兴趣
科普一下AHAs and vitamin C products
AHAs and vitamin C products


The distinctions between alpha hydroxy acids and vitamin C can be confusing because both make very similar claims. In reality, however, they are very different, and while each serves a unique purpose, there is no guarantee that either of them will actually have any effect on your skin.
Alpha hydroxy acids, or AHAs as they're commonly known, are found in everything from cleansers to night creams. Derived from various sources like sugar cane, milk and fruits, these acids retexturise skin by gently exfoliating the dry, dead outermost layers of skin while moisturising the newly revealed layers. AHAs are thought to be beneficial to complexions that have started to look dull, dry or flaky because it's believed they help give skin a new 'glow'. However, cynics claim that the exfoliation achieved by AHAs can also be effected by a quick scrub of the face with a flannel.

While the term AHA is widely used, there are actually various types of acids designed to achieve different results:


Glycolic acid is the most common type of acid used in skincare. Derived from the sugar cane plant, it is used primarily in chemical peels and serums because it has the strongest exfoliation properties.

Lactic acid, which comes from sour milk, has intense hydrating properties and is commonly found in moisturisers. Legend says that Cleopatra took advantage of lactic acid's benefits by regularly indulging in sour milk baths.

Salicylic acid is actually not an AHA. In fact, this acid (derived from willow bark) is considered a beta hydroxy acid because it works deeper in the skin to unclog pores and reduce fine lines. This acid is a great option for oily- and acne-prone skin.
While AHAs are exfoliants, vitamin C is a natural antioxidant that fights free radicals.

Skin is constantly assaulted by free radicals, or molecules formed in the skin when it is exposed to pollution or other environmental factors, like smoke or sunlight. Free radicals break down the collagen and elastin found in skin, which are essential for keeping skin firm and healthy. Vitamin C is thought to strengthen collagen and elastin in the dermis (the deepest layers of the skin) that has been damaged by free radicals.

While vitamin C may be effective, it loses its potency very quickly, which can make its presence in products worthless if not used immediately. There are many derivatives of vitamin C found in products, and studies have shown that the ingredient is most stable and effective in its L-ascorbic acid form (look for this name on the ingredients label). Packaging is important, too, as vitamin C can oxidise very quickly when exposed to air and light. If you're buying a product that contains vitamin C, look for one in an airtight brown glass bottle or metal tube, which will screen out light and prevent air from seeping in and breaking down the vitamin. Be sure to always secure the cap tightly and store it a cool, dark place to prolong its shelf life.

Both AHAs and vitamin C may help reduce signs of ageing, but it's thought you may see optimum results faster if you use them in conjunction with each other. If your skin is dry, use a vitamin C cream or serum in the morning under your regular moisturiser and an AHA-based cream at night. If you have oily or combination skin, an AHA or salicylic acid cleanser or toner is believed to work best in the morning, followed by a vitamin C serum at night.
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04-04-08 15:15操作
只看TAAA分享
good, 就是看得有点累。
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04-04-08 15:38操作
只看TAAA分享
AHA的作用就是纯粹的酸,把皮肤表面的一层腐蚀掉,这个dd用多了,皮肤会变薄。因为它本身不能区分老化细胞和正常细胞,只是把表面那一层去掉。一般来讲,老化细胞都堆积在皮肤表面。用多了,老化细胞去完了,就会接着腐蚀正常细胞。
VC也叫酸,但是不起酸的作用。他的作用的把人体内一种很重要的酶从被氧化的无用的状态还原成有用的状态。这种酶是人体中参与合成胶原质的(collagen,一种蛋白质)。所以VC也是一种抗氧化剂,但与VE的抗氧化机理完全不同。
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05-02-12 23:19操作
只看TAAA分享
like it ................................................[em07]
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05-02-12 23:45操作
只看TAAA分享
以下是引用ayxblue在2004-4-8 15:38:00的发言:
AHA的作用就是纯粹的酸,把皮肤表面的一层腐蚀掉,这个dd用多了,皮肤会变薄。因为它本身不能区分老化细胞和正常细胞,只是把表面那一层去掉。一般来讲,老化细胞都堆积在皮肤表面。用多了,老化细胞去完了,就会接着腐蚀正常细胞。
VC也叫酸,但是不起酸的作用。他的作用的把人体内一种很重要的酶从被氧化的无用的状态还原成有用的状态。这种酶是人体中参与合成胶原质的(collagen,一种蛋白质)。所以VC也是一种抗氧化剂,但与VE的抗氧化机理完全不同。

这个看着容易

[em01][em01][em01][em01][em01]
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05-02-13 01:09操作
只看TAAA分享
以下是引用ayxblue在2004-4-8 15:38:00的发言:
AHA的作用就是纯粹的酸,把皮肤表面的一层腐蚀掉,这个dd用多了,皮肤会变薄。因为它本身不能区分老化细胞和正常细胞,只是把表面那一层去掉。一般来讲,老化细胞都堆积在皮肤表面。用多了,老化细胞去完了,就会接着腐蚀正常细胞。
VC也叫酸,但是不起酸的作用。他的作用的把人体内一种很重要的酶从被氧化的无用的状态还原成有用的状态。这种酶是人体中参与合成胶原质的(collagen,一种蛋白质)。所以VC也是一种抗氧化剂,但与VE的抗氧化机理完全不同。

这个说法不全面。aha在低浓度的时候是一种保湿剂。较高浓度和适当PH值的时候,它的作用也不是‘腐蚀‘细胞,而是溶解脆弱的细胞联结, 从而使老化细胞脱落。 当然用的太频繁也是不好的, 但是适当使用不会伤害皮肤,还会促进皮肤更新。

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05-02-13 01:41操作
只看TAAA分享
说到浓度和PH值,选择VC产品也要考虑这两方面,PH值直接影响VC的吸收率,PH越低,吸收率越高,但相应的刺激也越大. 而浓度,对于VC来说浓度超过20%就没有什么意义了,就减少紫外线危害来说,最好的浓度配比是20%的VC+1%的VE.
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05-02-13 13:20操作
只看TAAA分享
很有用啊,而且大家好像都很懂得样子 :)
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05-02-13 14:16操作
只看TAAA分享
以下是引用ayxblue在2004-4-8 15:38:00的发言:
AHA的作用就是纯粹的酸,把皮肤表面的一层腐蚀掉,这个dd用多了,皮肤会变薄。因为它本身不能区分老化细胞和正常细胞,只是把表面那一层去掉。一般来讲,老化细胞都堆积在皮肤表面。用多了,老化细胞去完了,就会接着腐蚀正常细胞。
VC也叫酸,但是不起酸的作用。他的作用的把人体内一种很重要的酶从被氧化的无用的状态还原成有用的状态。这种酶是人体中参与合成胶原质的(collagen,一种蛋白质)。所以VC也是一种抗氧化剂,但与VE的抗氧化机理完全不同。


仰慕,那么BHA呢?
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05-02-13 15:15操作
只看TAAA分享
啊!这里专家真多啊!谢谢科普!
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