FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person *   BIOTECH GROWTH N V 2. Date of Event Requiring Statement (Month/Day/Year) 05/17/2011 3. Issuer Name and Ticker or Trading Symbol Radius Health, Inc. [NONE] (Last) (First) (Middle) SNIPWEG 26 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) CURACAO, P8 00000 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)

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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Series A-1 Convertible Preferred Stock (1)	  (2)	  (2)	Common Stock	409,400	$ (2)	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
BIOTECH GROWTH N V SNIPWEG 26 CURACAO, P8 00000	Â	  X	Â	Â
BB BIOTECH AG VORDERGASSE 3 SCHAFFHAUSEN, SWITZERLAND, V8 8200	Â	  X	Â	Â

Signatures

/s/ Michael Hutter, Signatory Authority for Biotech Growth N.V. and BB Biotech AG		06/03/2011
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Biotech Growth N.V. is a wholly-owned subsidiary of BB Biotech AG. Accordingly, BB Biotech AG may be deemed to be the indirect beneficial owner of the securities of Radius Health Inc. held directly or indirectly by Biotech Growth N.V. This Form 3 is filed jointly by BB Biotech and Biotech Growth N.V.
(2)	Each share of Series A-1 Convertible Preferred Stock has no expiration date and is convertible at any time, in whole or in part, at the election of the holder at a conversion ratio of 10 shares of Common Stock for every 1 share of Preferred Stock.

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