The increasingly popular products do not offer the same level of protection as the equivalent SPF sunscreen, the British Association of Dermatologists (BAD) has said.
The warning comes amid an alarming rise in skin cancer - diagnoses have rocketed by 16% in five years across England, new NHS figures show.
The increase in Bucks hasn’t been as substantial over the same five-year period.
In the Bucks Clinical Commissioning Group (CCG) area, there has been a 1.9% rise in the number of malignant melanoma tumours reported.
This is a specific type of skin cancer experts link to overexposure to the sun.
It is considered the most dangerous type of skin care.
The NHS says, it can usually be treated with surgery if it's found early.
If it has spread, you may need other treatments, such as radiotherapy.
While in Bucks cases have increased by 1.9%, nationally figures have increased by 13% with more than 15,000 cases reported.
In total, 950 of these were recorded in Bucks.
Matthew Gass, of the BAD, said: “Skin cancer cases have been on the rise since the 1970s and it is now the most common cancer in the UK. So it is not necessarily a surprise to see that the most recent skin cancer figures for England show that rates have risen again.”
He said while it is not possible to give a definitive reason for the rise in cases, it is “likely caused by an ageing population and better cancer registration practices”.
“It is also possible that changes to sun-seeking behaviour are a factor,” he said.
Mr Gass said in recent years there has been a big increase in the number of moisturisers and cosmetic products containing SPF (sun protection factor).
He said while these are tested in the same way as sunscreens, in reality they “tend to be applied much more thinly, and as such they don’t offer the same level of protection as the equivalent sunscreen”.
He said: “You should only rely on these when you’re getting brief, incidental sun exposure, for example if you are popping out to the shops.”
Keratinocyte cancer, also referred to as non-melanoma, is the most common form of skin cancer.
In 2019, 207,000 cases were diagnosed in England, a 17% rise in five years.
And cases of rare skin cancers rose by 24% over the same timeframe.
The most common cause of skin cancer is exposure to ultraviolet light from the sun or sunbeds, but “taking sensible precautions to protect your skin from the sun is likely to reduce your risk of developing a skin cancer in the future,” Mr Gass said.
He noted that the three main ways to better protect yourself from the sun are shade, clothing and sunscreen.
Mr Gass said that the BAD advises making good use of shade, particularly between 11am and 3pm when it’s most sunny, and wearing protective clothing, including hats and sunglasses in order to protect your skin from the sun.
“As a last line of defence, wear sunscreen with a minimum SPF of 30 and UVA protection,” he added.