Don't be a douche. He asked for advice, so give it to him. If we all used the search function there would be like 20 threads, and we wouldnt need you to be a mod.
I'm sorry that I'm not experienced with it, but erowid has a lot of information and this is what I can tell you.
4-Methylmethcathinone is a synthetic stimulant with empathogenic effects that is chemically similar to methcathinone. Between 2007 and 2009, it became available for purchase online, was used increasingly in Europe, Australia, and New Zealand, associated with several deaths, and then controlled in some countries as a result. Because of the similarity in names, it is sometimes confused with 'Methedrone' (4-methoxymethcathinone) or 'Methylone' (bk-MDMA).
At least two deaths in Scandinavia have been speculatively linked to "mephedrone" (4-methylmethcathinone) in the last fourteen months. 4-methylmethcathinone is similar in structure to cathinone (found in the Catha edulis plant) and methcathinone, both Schedule I chemicals in the United States. Its effects have been likened to cocaine, MDMA, and amphetamines, and it can elicit compulsive redosing in some users.
Negative effects related to 4-methylmethcathinone use that have appeared in online reports include skin rashes, numbness, headache, short-term memory effects and minor amnesia. A puzzling range of symptoms linked to heavier 4-methylmethcathinone doses have been reported in at least two cases. An account submitted to the Erowid Experience Report Vaults in December 2008 described skin discoloration, light-headedness, cramping and aches suggestive of strong vascular or allergic effects following a cumulative dose of 1.8 grams ingested over 20 hours. The person was hospitalized and monitored. Low-level symptoms persisted after the acute effects passed.
In May 2009, a description of similar effects, at a third of the dose and time (600 mg over 6 hours), was reported to Drugs-Forum. In this account as well, low-level symptoms persisted after the acute effects passed.
People reporting such effects are encouraged to consult a medical professional. Written accounts should give as much pertinent detail as possible when describing symptoms, including dose and timing data, whether other substances, medicines or supplements were ingested, and how recently and how much the person slept. Updates on the status of symptoms over days, weeks or months may be helpful for the development of measures to improve safety and protect users.
I do believe there is a report done by Alexander Shulgin as well. I couldn't find it with a 5 second google search, so I'll leave you to find it.